This invention relates generally to a reference stop for use in a lathe for providing a fixed surface from which measurements can be made for applying tools to a workpiece being worked in the lathe.
Lathes are typically provided with a chuck which is used to grip raw stock to be worked, and means for rotating the chuck at a high rate of speed, which can approach thousands of revolutions per minute ("RPM "). A draw tube may be connected to the chuck for rotation with the chuck. Raw stock passes through the draw tube and is engaged by the chuck during operation of the lathe.
Typically, raw stock is inserted through one end of the machine through the draw tube, and then on through the chuck, where the stock is gripped. However, although the workstock is typically inserted into the backside of the chuck through the draw tube, in certain operations it is necessary to insert the stock directly into the front side of the chuck and on into the draw tube. This is necessary when the stock must be worked at a particular point along its length, and that length dimension, as measured from the end of the stock now within the draw tube, must be accurately measured. A common method of measuring this point is through a simple trial and error approach. The stock is repeatedly inserted through the front end of the chuck into the draw tube and tightened down, and measurements taken until the correct distance from the free end of the workstock to the working point of the lathe tool to be used is found. This can be a tedious, cumbersome, and time-consuming endeavor and reduces the efficiency of operation of the lathe, and further, increases labor costs associated with production. Other means have included devices for attachment of a reference stop to the draw tube. However, because in conventional lathes the draw tube moves rearwardly during the tightening of jaws of the chuck when gripping the stock, and forwardly to loosen the chuck jaws, such reference stops can become difficult to adjust to the proper reference distance.
Accordingly, there exists a need for a means for facilitating setup of stock within a chuck to present a predetermined point of the stock to a desired lathe tool.